Crash zones are frequently incorporated in rail-mounted vehicles in order to improve their deformation behavior in collisions. The aim of these improvement measures is to absorb the impact energy in such a way that crush zones that are deformable in a defined manner convert this energy into deformation energy and in the process the loads to which the persons in the vehicle are exposed are minimized, as well as to ensure that the survival spaces in the vehicle are not too severely deformed in order to reduce the likelihood of injury to the vehicle occupants.
For this purpose extensive areas of the rail vehicle structure can on the one hand be designed so as to be able to absorb the deformation energy in a targeted manner or special crash modules are mounted onto the front and rear structure of the rail vehicle. The latter approach is advantageous because a repair after a collision is facilitated owing to the easy accessibility of said crash modules.
Collisions between rail vehicles take place essentially in the direction of the vehicle longitudinal axis, while a difference in level, due for example to different loading states of the vehicles involved in the collision, may under certain conditions lead to what is termed “override”. In order to prevent this effect, protection in the form of an anti-override structure is provided in most cases, with plates provided with a tooth structure typically being mounted onto each vehicle. In the event of a collision said plates interlock and prevent the override.
A further problem presents itself in the case of rail vehicles for which there exists an increased risk of a collision with an obstacle other than another rail vehicle (in particular streetcars). It is necessary to make provision for a much broader range of collision scenarios, with unilaterally offset and transverse collisions of conventional crush zones or crash modules, which essentially are designed to withstand collisions in the longitudinal direction, are handled only to an unsatisfactory extent. The EN 15277 standard, for example, specifies crashworthiness requirements to be met by streetcar vehicles in the event of a collision with a vehicle of identical design at 15 km/h with a 40 mm vertical offset and a collision with a 3-tonne obstacle inclined at a 45-degree angle at a speed of 25 km/h (collision scenario: train in collision with a light commercial vehicle at a level crossing).
Conventional crash modules designed to handle longitudinal collisions are often unable to absorb said transverse loading satisfactorily, since said crash modules are in this case subject to a bending and shearing stress under which the affected crash element will buckle sideways in the absence of any precautionary measures to provide transverse support. WO 2009/040309 may be cited by way of example. Although the crash module disclosed therein prevents the overriding of the rail vehicles, it provides no deformation conditions suitable for absorbing transverse collisions. A corresponding configuration of the known crash elements in a manner that enables them to handle both longitudinal and transverse collisions equally well would lead to extremely costly, complicated and heavy crash elements which are not suitable for use on rail vehicles.